pedwfrontend/memory-bank/patterns.md

Patterns

Entry Template

date: YYYY-MM-DD
author: <agent|name>
scope: <files/routes/features>
type: pattern
rationale: <why>
impact: <user/system/security/i18n/a11y>
status: accepted|superseded

Pattern:
When to use:
Example paths:

---

P-001: Thin Pages, Reusable Logic Elsewhere

date: 2026-03-11
author: Cline
scope: pages/, components/, lib/, actions/
type: pattern
rationale: Improve maintainability and reduce route-level complexity.
impact: Better testability and safer incremental changes.
status: accepted

Pattern: Keep route pages focused on composition and orchestration; place reusable behavior in lib/, components/, or actions/.

When to use:

• New features in existing routes
• Refactors reducing duplication across pages/components

Example paths:

• pages/newappeal/**
• components/newappeal/**
• actions/index.js

P-002: EN/CY Parity for User-Facing Changes

date: 2026-03-11
author: Cline
scope: locales/, i18n.js, next.config.js, user-facing pages
type: pattern
rationale: Service requires bilingual consistency and reliable route behavior.
impact: Prevents locale divergence and citizen confusion.
status: accepted

Pattern: Any user-facing change should include EN and CY text/route validation as part of done checks.

When to use:

• New/changed labels, messages, headings
• New/changed route aliases or rewrites

Example paths:

• locales/en/**, locales/cy/**
• next.config.js, i18n.js

P-003: Shared Relay Policy via Middleware (No Endpoint Drift)

date: 2026-03-24
author: Cline
scope: pages/api/middleware/relayForwarding.js, pages/api/endpoint/*_api.js relay GET handlers
type: pattern
rationale: Keep reliability and logging policy centralized so endpoint handlers remain thin and behavior stays consistent as relay surface evolves.
impact: Reduces duplication/drift in timeout/retry/error behavior and supports safer incremental endpoint migration/hardening.
status: accepted

Pattern: Implement retry/timeout/redacted structured logging in shared relay middleware and keep endpoint handlers focused on validation, transform, and route-level response contracts.

When to use:

• Any new or migrated relay-backed endpoint
• Any relay reliability/logging policy update

Example paths:

• pages/api/middleware/relayForwarding.js
• pages/api/endpoint/getadvancedsearch_api.js
• pages/api/endpoint/getdnscoords_api.js
• tests/phase21/relay-forwarding-hardening.test.cjs

P-004: Relay Policy Change Bundle (Governance + Smoke + Rollback)

date: 2026-03-24
author: Cline
scope: relay policy changes + rollout documentation
type: pattern
rationale: Relay reliability changes can alter runtime behavior without changing endpoint contracts; bundle process controls and operational checks together to reduce regression risk.
impact: Improves release confidence and standardizes operational readiness for relay policy updates.
status: accepted

Pattern: For relay timeout/retry/logging policy updates, ship one documentation bundle that includes governance checklist, non-prod smoke matrix, monitoring checks, and rollback instructions.

When to use:

• Any change to retry classification, timeout defaults/bounds, or relay logging behavior
• Any change to relay environment tuning guidance

Example paths:

• context/runbook.md
• memory-bank/change-log.md
• memory-bank/decisions.md